The subject matter disclosed herein relates to a load protection system for a turbine, and more specifically to a load protection system for controlling a turbine that allows a load floor that supports a minimum load.
Gas turbines are commonly used in load charging environments such as power generation services. The gas turbine is employed to supply power to an electrical power grid and is used to maintain a specified grid frequency range during operation. Specifically, the output of the gas turbine is adjusted in an effort to counteract grid frequency disturbances. Thus, if the specified grid frequency range is exceeded, then the gas turbine sheds load. That is, the gas turbine is under-fired and produces less power than what is typically needed by the power grid in the event the power grid exceeds the specified grid frequency range.
There are various factors governing the control of gas turbines such as, for example, emissions compliance and service life. Under-firing of the gas turbine may lead to increased emissions. In an effort to comply with emissions requirements, the gas turbine is typically kept above a minimum firing temperature (or minimum technical load if allowed). There is a balance between maintaining the specified grid frequency range while at the same time complying with emissions requirements.